Objective To explore the relationgship and the clinical significance between serum neutrophil gelatinaseassociated lipocalin (NGAL) levels and fractional flow reserve(FFR) in patients with coronary intermediate lesions. Methods Clinical data of 244 patients with coronary intermediate lesions (the degree of coronary artery stenosis ranged from 50% to 70%) diagnosed by coronary angiography and FFR was performed in The Second Affiliated Hospital of Hainan Medical University from January 2019 to January 2021 were retrospectively analyzed. According to the FFR, the patients were divided into two groups: the FFR＜0.8 group (n=83) and the FFR≥0.8 group (n=161). Serum NGAL, total cholesterol, triglyceride, creatinine and blood glucose were detected before coronary angiography. The correlation between NGAL and FFR was explored by correlation analysis, multivariate logistic regression analysis and Receiver Operating Characteristic (ROC) curve. Results The levels of serum NGAL in the FFR＜0.8 group was significantly higher than that in the FFR≥0.8 group ［71.93(50.12,150.45) μg/L vs. 34.99 (24.47,50.58)μg/L, P＜0.001］, and NGAL level was negatively correlated with FFR (r=0.505，P＜0.001). Multivariate logistic regression analysis was revealed that NGAL was an independent predictor for myocardial ischemia in patients with coronary intermediate lesions (OR＝7.387，95%CI：1.017～1.041，P＜0.001)．ROC analysis showed that the best cut-off vlaue was 52.51μg/L with the biggest sum of sensitivity and specificity (79.50% and 73.49%，respectively)，when FFR=0.8 as a boundary. Conclusion The elevated serum level of NGAL is an independent risk factor for the decrease of FFR in patients with coronary intermediate lesions，and NGAL may be an potential biological index o to diagnose myocardial ischemia in patients with coronary intermediate lesions.